Evaluation of growth hormone secretion after completion of therapy

Background: Growth hormone (GH) reserve in young adults previously diagnose d as having GH insufficiency, who were treated with human (h)GH replacement in childhood needs confirmation in adulthood. Methods: Nine patients (seven males, two females; two empty cella, one hypo plasia of the hypophysis and six with idiopathic GH deficiency) diagnosed a s having GH insufficiency by the insulin tolerance test (ITT) and dopamine stimulation test in childhood (mean age 12.8 +/- 2.6 years) were retested a t completion of linear growth (mean age 21.0 +/- 3.0 years), 4.6 +/- 1.6 ye ars after discontinuation of hGH therapy. Results: At the initial diagnosis, seven had complete and two had partial G H deficiency. At diagnosis, the mean peak GH response to ITT and dopamine w as 4.8 +/- 4.08 and 3.4 +/- 2.9 mU/L, respectively. Ar retesting. the mean GH response to ITT and dopamine stimulation was 3.5 +/- 2.5 and 3.3 +/- 3.1 mU/L, respectively (P=0.91 and 0.96, respectively). During hGH therapy, me an height velocity increased from 3.5 +/- 1.9 cm/year at diagnosis to 9.9 /- 3.64 cm/year during the first year (P = 0.002). One of nine children dia gnosed as having Gli insufficiency who was treated with hGH replacement had normal growth hormone secretion at completion of linear growth. Conclusions: All GH-insufficient children should be retested after completi on of their hGH treatment and lineal growth to identify those who are truly GH insufficient and who may benefit from GH therapy in adulthood.